The present invention relates to polyvinyl alcohol(PVA) graft terpolymers and, more particalary, the invention relates to acrylate/maleic anhydride copolymer grafted polyvinyl alcohol graft terpolymers.
Polyvinyl alcohol has been recognized as a hydrophilic polymer with excellent physical and mechanical properties. It has been used in such areas as adhesives, emulsions, textitles and in solvent barrier coatings. However, being a water soluble polymer, polyvinyl alcohol has poor water resistance. Also, unplasticized vinyl alcohol polymers show little or no thermo-plasticity before the occurence of decomposition. For overcoming these drawbacks pertaining to PVA, modification of PVA through the use of comonomers, graftings or post reaction is known in the art.
In our previous papers entitled, "Studies of Reactions with Polymers. I. The Reaction of Maleic Anhydride with PVA and th Properties of the Resultant" and "Studies of Reactions with Polymers. II. The Reaction of Maleic Anhydride with Acrylonitrile onto PVA and the Properties of the Resultant" J. Appl. Polym. Sci. 30, 3895 and 4045 (1985), we reported the synthesis of PVA graft copolymers to improve the water resistance of PVA by grafting maleic anhydride (MA) and acrylonitrile using potassium persulfate as an initiator. It has been found that the MA in the side chain would rearrange to form a keto-olefinic structure.
Graft copolymers have been generally synthesized either by polymerization a monomer from an initiating site on a backbone or by linking two different polymers through a polymer reaction. However, it is impossible to synthesize the grafted side chains with an anhydride structure by grafting MA onto PVA by using former grafting methed.